Referring to U.S. Pat. No. 8,896,007 B2, as illustrated in FIG. 1, a conventional vertical light-emitting diode includes a N-type semiconductor layer 1, an active layer 2 and a P-type semiconductor layer 3, which constitute a sandwich structure. Under the P-type semiconductor layer 3, a metallic reflecting layer 4, a metallic buffer layer 5, a binding layer 6, a silicon substrate 7 and a P-type electrode 8 are provided in turn. Moreover, the surface of the N-type semiconductor layer 1 may be roughened so as to enhance luminous emittance, and provided for disposing a N-type electrode 9. Thereby, after a voltage is applied between the N-type electrode 9 and the P-type electrode 8, electrons are provided by the N-type semiconductor layer 1, while electron holes are provided by the P-type semiconductor layer 3. Light is generated, after the electrons and the electron holes are combined in the active layer 2.
In this conventional technology, a current barrier layer 10 is provided between the metallic reflecting layer 4 and the metallic buffer layer 5. The current barrier layer 10 is provided with higher resistance, allowing smaller current passing therethrough and further dispersing current, so as to enhance luminous uniformity and overall brightness. Moreover, for protecting the metallic reflecting layer 4, a protective layer 11 is further provided for sheltering the metallic reflecting layer 4, so as to prevent the metallic reflecting layer 4 from being oxidized to reduce reflectivity due to the subsequent manufacturing process.
However, the problem encountered by this conventional structure is that higher resistance is provided for the current barrier layer 10, such that higher temperature is readily generated in the current barrier layer 10 after this conventional structure is used for a long period of time. Thus, the metallic reflecting layer 4 contacted with the current barrier layer 10 is apt to crack when being contacted with high temperature. Thereby, reflectivity of the metallic reflecting layer 4 may be reduced significantly, and then, is impossible for fulfilling the usage requirement.